One family member of mine is like that. I always get that vibe, in every single conversation that lasts more than half a minute, whether with me or someone else. Since I'm doing the "skip through the bullshit" interruptions, it is less evident in conversations with me, as I mostly prevent it by cutting him off to skip to the point.
Generally, what he does is giving background information, little details, most often interpersonal, that indicate dissatisfaction and something negative/bad happening to him. It may be that he didn't get any help from someone or someone didn't say anything positive or said something negative about him. It may be that he didn't get what he expected from someone or simply something about his life situation. For the latter, an example would be him complaining about the fact that he doesn't have enough money as in "I was going to buy a new coat but I didn't have money for it. I had to give back the loans I took last month because I didn't have money too. The situation is getting worse and worse, I can barely scrap money to pay for the bus." and this is happening in the middle of him getting to his point about something absolutely unrelated, like someone asking how much he paid for something the other day. It's not the best example though. It may be something else, something he doesn't like that he does every day, etc..
So sometimes this is pure manipulation, trying to make someone to feel sorry for him and provide him with some kind of help (and he may do this to another person if his expectation isn't met). But that's not always the case, sometimes he just complains about how his situation is bad and how he doesn't like something, is doing something, "has" to do something, etc.. Those cases, he just wants people to feel sorry for him.
What do you think about such behavior - telling unrelated details in conversations (even formal conversations with unknown people!) to make others feel sorry for him/her? (exclude the manipulation part)